Well screen and perforation cleaner



W. TARKINGTON WELL SCREEN AND PERFORATION CLEANER sept. 9, 1947.

, 1944 u 3 Sheets-Sheet 1 Filed Aug. 1

ATTORNEY Filed Aug. l, 1944 3 Sheets-Sheet 2 ATTORNEY Sept. 9, 1947. 'w. TARKINGTON WELL SCREEN AND PERFORATION CLEANER 3 Sheets-Shed; 5

FiledAug. 1, 1944 12 [fao Patented Sept. 9, 1947 UNITED STATES ?ATENT OFFICE WELL SCREEN AND PERFORATION CLEANER 4 Claims.

My invention relates to well screen and perforation cleaners utilizing the hydrostatic pressure in an oil well to effect the clearing of mud and other debris from the slots and perforations in well screens and the like, said screens usually located radjacent the producing formations in wells. Such perforated sections of well screens are usually seated on the bottom of the well and extend upwardly telescopically into the water string of oil well casing. Frequently the uppermost end of the liner is provided with a fixed packer to form a seal with the wall of the casing in which it is seated so as to exclude mud, shale, sand and the like from the bore of the well. In certain instances the screen joints are interspersed with casing joints, having no perforations. The bottommost section of the liner is sealed by various means, usually a back pressure valve, to prevent the entrance of sand, shale, etc., at the bottom.

Screen and perforation cleaners of the hydrostatic type heretofore used, operable by means of a hoist and cable, usually are provided with a packing means to form a seal between the cleaner and the perforated liner wall, a low pressure chamber above the packing means opening to the well pressure below the packing means, provided with valvular means for exposing the low pressure chamber to the well pressure, thereby causing a low pressure area to be formed within the annular isolated section of screen below the packer.

The primary object of my invention is to provide a screen and perforation cleaner, having a telescopic sleeve valve connected between a low pressure chamber above the valve and a load receiving chamber below the valve, having identically the same construction, in so far as valvular control is concerned, as the bailer patented to me in Patent No. 2,198,490, dated April 23, 1946, except that the bottom of the bailer shoe is threaded for connection to it of a combined packer and seating device described herein. The cleaner is provided with means for seating the tool at a predetermined Zone in the well screen and for the simultaneous opening kof the sleeve valve to communicate the well pressure to the low pressure chamber, thereby radially expanding the packers tightly against the wall of the screen and drawing a charge into the load receiving chamber through the isolated section of perforations. When the charge is drawn, the low pressure chamber is equaliZed-with the fluid pressure in the well, thereby permitting the packers to disengage themselves.

One other object is to provide automatically operable hydraulic means for seating the tool at a predetermined depth in the well fluid by closing a hydraulically operable Valve located in the combined packer and seating device, by spudding the tool (two or three feet), and also means for the automatic release of the packers from the liner wall, when the low pressure chamber is filled, and means for withdrawal of the tool easily without consequent disrupting of the rubber packers on the burrs usually projecting into a liner.

One further object is to provide an improved cleaner whereby the hydrostatic bailer mentioned herein may be quickly transformed into a cleaner by simply connecting the combined. packer and seating device to the bottom valve of the bailer. Another object of the invention is to relieve the operating cable from as much stress as possible, by opening the tool by a downward movement. Should a second downward movement be actuated by the descending iluid head when the low pressure chamber is opened, the automatically closable valve means will act to check such movement.

This cleaner is also effective by eliminating the topmost packer from the mandrel. The bottornmost packer is essential in seating the device. In this operation, the descending fluid column is unobstructed, until it meets with resistance at the bottom packer which forms a seat, in combination with the closed valve contained therein. This operation drives the uid outwardly through the perforations, opening perforations where they are not too tightly clogged.

Further objects appear herein:

Referring more particularly to the drawings: Fig. 1 shows an elevational side View of applicants well screen and perforation cleaner. Fig. 2 is a partial sectional side View of 2--2 shown at Fig. 1. Figure 3 is a partial sectional side view of that part of Fig. 1 indicated at 3-3. Fig. 4 is a sectional side View of a part of Fig. 1 indicated by 4-4 at Fig. 1. Fig. 5 is a sectional view of Fig. 4 taken at 5 5 of Fig. 4. Fig. 6 is a sectional view taken at 6 6 of Fig. 4. Fig. 7 is an enlargedv sectional View showin-g detail of the valve generally indicated at 1-1 of Fig. 2. Fig. 8 is a view taken at section 8-8 of Fig. '7. Fig. 9 is an enlarged View of part of top 9-9 of Fig. 2 showing construction of an auxiliary dumping valve. Fig. 2, Fig. 3, and Fig. 4, 'show the general combination in sectional view in its regular assembly. Fig. 4 shows the combined packer and seating device normally positioned in a usual section of well screen. Section 9 9 of Fig, 2 illustrates a closed top adapted for cable (not shown) connection, with means for relieving eX- cess pressure while withdrawing the tool from a well. A low pressure chamber IB may be constructed from one or more lengths of tubular material and may be of varying lengths, dependent on the height of the well derrick. A telescopic sleeve valve is attached to the "bottommost end of low pressure chamber Ill, the valve more generally indicated at 'I-'i at Fig. 2, while depending therefrom is a load receiving chamber 30 of a suitable length (usually the length of the lowV pressure chamber I), provided with a connection for a bottom bailer valve 36 (Fig. 3) threaded at 44 to receive the top connection of the combined packer and seating device shown in detail at Fig. 4. Located in the top 9-9 of'Fig. 2 is a threaded nipple Si supporting a seat for a co operating'ball valve 'I urged into'compression for various relief pressures by means of a helical spring3`, a disc 5', and aset screw 2. An opening 4 isfor fluid pressure escape. The ball valve urged by spring tension acts to oppose all well pressure while the tool is being lowered into the fluid to the zone of operation, and to retain fluid in the tool at apredetermined pressure in the pressure chamber on elevation of the tool. Attached to low pressure chamber' I0, preferably threadedly connected thereto at Illa is the sleeve valve inner cylindrical member or element II, shown in moredetailat Fig. '7. The lower end of the sleeve valvei outer cylindrical element I2 is threadedly attached to top ofl load chamber 3i)r at Sil-LL The valve comprises outer and inner concentric cylindrical elements. Inner cylindrical element II telescopes into outer cylindrical element I2, the flanged shoulder I5 formed on element II, beingV limited in longitudinal movement by abutments at 8l) and IS-a respectively on the element I2. On the lowermost end portion of element II, an inner valve member I8 with valve ports (Fig. '7), 2|, 22A and 23 therein is formed. The limited reciprocal movement of element Il within element I2 is adapted to reciprocally alternatively open and close` port I4 in element I2 to act as a closure for port I4. An intermediate sleeve valveY member I'I is mounted in outer cylindrical element I2 below port I4 and inner cylindrical member 'I8 is` slidably movable within the intermediate sleeve valve member Il; Ports ZI', 22 and 23 inthe inner sleeve valve member on the lowermost endportion of element II are adapted to register with ports 83, 84 and B5 in the intermediate sleeve valve member II when the cylindrical element II' actuated by the chamb-er in is telescoped within outer cylindrical element I21to open the valve (Fig. 2), but when the valve parts` I-I` and: I2 are in their extended relation, valve portSZI; 22' and 23 are closed (Fig. 7), being moved into the imperforate upper portion of the intermediate' sleeve II. Ports 2I, 22 and 23 'are held'in longitudinal alignment with ports 33,y B4" and`85 by means of a key 'I9 and a cooperating keyway 19-a for-med on the elements BI and I2 respectively; Ai set screw 86 extends through element I-2V toward the port B5 in sleeve I'I. toy hold the sleeve against rotation. Intermediate valve member I'I engages packing gasket I5 andthe downwardly facing abutment formed in element I2 at Iii-47.. The lowermost end of I'I is seated concentrically upon the uppermost end ofloadchamber threaded into the element I2 at' iiD-47.. The inside diameter of 3D is slightly smaller (Fig. 8) than the outside diameter of member I'I. Casing 3l) is threaded into element I2 and threaded upwardly to firmly engage and hold the sleeve Il within the element I2. The intermediate valve member I'I is provided with exterior longitudinal conduits I9 to permit passage of fluid from the load receiving chamber 30 upwardly through the open ports of the valve and into the low pressure chamber I0. Intermediate valve member I'I has a vertical fluid passage IS communicating its lowermost end with the port conduit I9 and opening outwardly at the upper end of the member II to communicate with port I4 in the outer cylindrical element I2. The upper portion of fluid passage I8 is enlarged and in this enlarged portion is a ball valve seat at thevlower end` thereof. Ball valve 82 is adapted to rest on the valve seat and the helical spring 8l above the ball valve urges the ball valve into closed position, preventing downward iow of fluid through the passage I8, but when the valve ports 2l, 22 and 23 vare in their closed position, fluid may pass upwardly through the passage I8 and outwardly through the port I4 to reduce any excessive pressure within the load receiving chamber. The lower end of element Il, to form an inside valve member 18, is provided with solid type packing rings 2B and 24. Packing ring 2B isfollowed by close-tting metal sleeve 25, havingfour ports adapted to align with ports formed on the inside inner valve member 18 and held against rotation by slot and pin 88, a packing ring 2li follows 25 and a close fitting metal sleeve 25 extends slightly past the lowermost part of '18 to permit packing adjustment. A metal disc 2 with opening for stud, following 26, and a stud with retaining nut 2S screwed into the lowerrnost part of 'I8 provide an adjustment for the packings.

In operation, when the valve contacts fluid while descending in a well, the action of the iiuid pressure against the disc 2'I urges both metal sleeves and packing rings upwardly, operating to expand both packing rings against the inside wall of intermediate valve member Il and the outer surface of the inside valve member 18, insuring a perfect seal against fluid entering the low pressure chamber while submergence is taking place.

the cleaner emerges from the fluid, the confined high pressure trapped in the low pressure chamber I acts to distend the-packings 2S and 22 from the ports 2 I, 22 and 23, thereby reserving a pressure in the pressure chamber gauged by tension on the spring-pressed ball valve seated in the top I (Fig. 2).

A bailer bottomfvalve is threadedly attached to load receiving chamber 30' (Fig; 3). The valve comprises a shoe 3l with sleeve Sii threadedly connected thereinto and having an opening SS-a in one side. Shoe 3l has an opening 38 adapted to register with opening iQ-a in the sleeve 3G. Removable combined partition andv seat I is seated within shoe 3l and carries a one-way flavalve It for retaining the load in the load receiving chamber 3Q. Openings are brought into registry by well known manually operable means by rotating the sleeve 35 relative to the shoe 3l until opening E't9-Ci is in alignment with opening 3S. Shoe 3'! is threaded at its lowermost end 44 for connection to the topmost end of a combined packer and seating device shown at Fig. 4.

The combined packer and seating device comprises a tubular mandrel 57 with circumferential shoulders BI and 59 thereon for seating spaced packers 52 and 5l'. An inner tubular member 41-a is welded therein at 16 and 55. Inner tubular member i1- a to form a by-pass duct is provided with slots 12, 1| and 56 longitudinally formed on the outside thereof, said slots terminating and cooperating with the ports 50 and 50-a. The purpose of these by-pass slots is herein shown. Substantially mounted on the outside of the mandrel 51 are rubber packing elements 52 and 51. The upper packing element 52 as well as the lower packing element 51, are commonly known as swab cups and are well adapted to this service. Packing element 52 is seated in the usual position (ilexible end upwardly), on metal thimble 53 supported on the shoulder 9|. Packing element 51 forms an opposing packer as well as a seating element, and is held firmly in an inverted position (flexible end downwardly), on metal thimble 58 rmly against the shoulder 59. Both packers are rmly seated in thimbles 53 and 58 by means of screw thread pressure of pipe couplings i5 and 5D urged against cylindrical rings 5t-a and ri-b respectively. The cylindrical ring Siia is provided with ports 513 and 55-a cooperating with ports in mandrel d1, communieating with the slots 12, 15 and 55 formed in the inner tubular member @l1-a to permit the by-passage of fluid through the mandrel 4i. The

port 13 in i1- a with a corresponding port in i1 are formed in the inner tubular member 41-a and mandrel 41 respectively, Port 55 is of slightly larger dimensions than port 13 to afford a welding face for sealing the tubular parts together. Inner tubular member i1-a ts snugly within mandrel [i1 as shown at Figs. 4 and 5. Inner tubular member i1-a, to form a one-way inlet passageway from port 55 to the bailer bottom, is sealed at its lowermost end 15. The assembled parts i1 and i1-a may now be considered as an integral member with the interior of part l1-U. providing the main bore of the mandrel. A back-pressure valve comprising a body 6|, a seat 53, a ball valve 55 and a cooperating cage is threadedly attached into pipe coupling 5|). The seat, ball and cage are Well known in the art of well pumping, but in this instance are placed in an inverted position for reasons herein explained. A pipe coupling el' and a plug 63 with ample fiuid passage perforations 56, are threadedly attached to the lowermost end of the valve body 5|. ample fluid by-passage through the cage 54, the valve seat 53 (the steel valve ball 66 normally remaining apart from its seat 53, dependent on the lowering speed), upwardly through the valve body 6|, and through the slots 12 and 55 and into the well fluid head through ports 5G and 50--a while the combination is descending in a well screen or liner having a fluid head, but the entry of any hydrostatic well pressure into the low pressure chamber will be through the port 55 located between the opposing packers. Thus, the screen and perforation cleaner shown at Fig. 1 can be moved with reasonable speed upwardly and downwardly within a well casing or liner containing fluid where the packers 52 and 51 are of a slidable t. It will be understood that the opposing ends of the packers are of a very flexible nature and easily expanded. Their extreme radial diameter is somewhat less when not expanded, than that of the inside diameter of the perforated well screen 5| (Fig. 6), which shows a sectional view taken at 6 5 Fig. 4. They are also much less in diameter than the well casing above the screen, which permits the tool to descend rapidly through the fluid. When the The device (Fig. 4) is thus provided momentum of the tool is reduced above the mouth of the screen, the ball valve assumes its normal position (removed from its seat).

In operation, the screen and perforation cleaner is lowered into a well containing Iiuid by means of a cable and hoist (not shown) attached to top i, and operable by hoist (not shown) The lowpressure chamber l0 has considerable weight, even while submerged in fluid. On elevation of the cleaner to lower into a well the sleeve valve shown at Fig. 2, assumes its normally closed position as shown at Fig. 7, by means of the suspended weight of the loading chamber shown at Fig. 3 and the combined packer and seating device shown at Fig. 4, the ports in the inner sleeve valve member 13 being drawn upwardly into the imperforate portion of the intermediate sleeve valve member |1. Since the screen or liner to be cleaned occupies only a small per centum of the bottom portion of the lineal depth of the well, the cleaner may be lowered rapidly without interference cr accidental opening of the sleeve valve Fig. 7, until the cleaner approaches the top of the liner or reduced diametrical section of the well when the speed of the lowering cable is reduced to a slow rate by the operator controlling the hoist. When the Zone of operation is reached. the tool is stopped by the operator for an instant. Therefore at the zone of operation the tool is permitted to drop rapidli7 for several feet. This action, (the resistant fluid to the downwardly facing packer) thrusts the Valve ball 55 against its seat 53, when urged by the dynamic rush of fluid upwardly through the seat 63, resulting in a sudden stoppage of the packer 51 on the uid below the packer. This stoppage is sufficient to cause immediate telescoping of the sleeve valve elements Il and I 2 (Fig. 2) with consequent opening of the sleeve valve ports, establishing communication of the hydrostatic fluid pressure to the low pressure chamber above the sleeve valve. Since the openings to the low pressure chamber are through the port 55 and through the registered sleeve valve ports, a low pressure Zone is established between the packers 52 and 51, and the hydrostatic pressure above the packer 52 and below the packer 5l acts to expand both the packers tightly radially against the inside wall of the perforated liner 5| until the atmospheric pressure in chamber lil is equalized with the Well pressure. When the low pressure chamber ID is thus equalized with that of the well fluid head, packers 52 and 51 automatically break their sealing contact with the liner wall 5|, and the tool can now be easily withdrawn from the well for unloading. In emerging the excess pressure in chamber IG will find relief through seat 1. On elevation, valve parts and I2 re-assume their normally closed position. The loading chamber l0 containing the debris recovered from the operation is unloaded through the registered openings 38 and 38 (Fig. 3) of the bottom bailer valve, which are brought into alignment by well known manually operated means. The retained pressure in chamber li will act to expel the load.

When the pressure in chamber I5 is exhausted or reduced through the loading chamber, there will yet remain in the pressure chamber an amount of fluid. An auxiliary valve located in the top and in a bore 94 spaced apart from the main bore of the relief valve hastens the drainage of the remaining fluid. Fig. 9 shows a partial sectional view of the top, and the valve is generally indicated by the numerals to 94 inclusive. Longitudinal bore 9| intersects lateral opening 94 communicating the pressure chamber lil .to ,atmosphericplessure "Threaded cylindrical element 90 `has an upwardly extending tubular portion smaller diametrically than the bore 9i, sufficient to permit compression of a helical spring 93 around the tubular part. A ball valve 92 is shown in its normal position, urged by spring pressure against an outer seat formed at the upper part of the bore 9 l. The topmost of the cylindrical element S9 has a cooperating inner seat for the ball 92. T'he spring is calibrated te yield slightly to atmospheric pressure from without the tool against the ball valve when a differential occurs in unloading. But the ball will quickly engage the seat at upper end of element 99, when the cleaner is submerging in fluid. l en the low pressure chamber I9 is equalized wh-n the well pressure at the bottom of the well, the ball moves upwardly to its outer seat or normal position to trap the pressure in the chamber. The ainriliary valve is automatically operable; te close the pressure chamber to the fluid while submerging to confine the trapped pressure in the chamber while emerging, and to admit atmospheric pressure to the pressure chamber when a vacuum is formed during the unloading process. The amount of fluid entering the pressure chamber in submergence is negligible.

What I claim is:

1. In a screen and perforation cleaner for oil wells, a low pressure chamber with a one-way inwardly opening valve for retaining a load in said chamber, a threaded connection on said one-wal7 valve connecting it with a combined packer and seating device, said packer and seating device comprising a hollow mandrel with opposing packers mounted thereon with means for bypass-- ing of Well fluid, said means comprising longitudinally formed ducts in the mandrel, the terminals of the ducts opening outwardly of the mandrel at a point above the topmost packer and at a point outwardly from the mandrel below the bottommost packer, an outward opening in said mandrel communicating with the main bore of said mandrel connected to the load retaining valve, said opening positioned between the packers and independent of the ducts, means for seating the packer and opening the low pressure chamber to the well pressure, comprising a seat and ball valve, a cage to support said ball independent of the seat while submergence is taking place at normal speed, said device being arranged to be suddenly dropped a short distance to close said ball valve and open said load retaining valve to well pressure while submerged in the well.

2, In a screen and perforation cleaning device for oil wells having iiuid head, a tubular vacuum of said ducts comprising a seat, inverted cage, and an upwardly closing valve ball, operating to close hydraulically at a predetermined point in' the screen to seat the device, and to expand the packings mounting the device against the inner screen wall until a charge is taken through the openings in said screen,

3. In a screen and perforation cleaning attachment for connection to the lower end of an oil well bailer operable by vacuum means under pressure, said attachment comprising a hollow mandrel having a down-facing swab cup mounted on the lower end thereof, said mandrel provided with ducts terminating outwardly of the mandrel at the ends of said mandrel above and below said swab cup, said ducts independent of the main bore in said mandrel, said main bore opening outwardly above said swab cup and arranged to communicate with the vacuum vchamber in said bailer above, valvular means connected to the mandrel ducts comprising a seat, an inverted cage supporting a valve ball when the valve is in its normally open position, said ball valve being arranged to seat upwardly upon the seat to close the ducts and seat the cleaning attachment by hydraulic pressure and to take a charge into the bailer above and to disengage the liner walls after receiving said charge.

4. In a screen and perforation cleaning device for connection to an oil well cleaning tool having a low pressure chamber, a seating and packing device comprising a hollow mandrel with opposing packing elements spaced apart thereon operating to isolate a perforated section of casing, fluid ducts formed longitudinally in said mandrel terminating outwardly from the mandrel above and below the packers, an outward opening in the mandrel between the opposing packers and terminating in main bore in the mandrel arranged to communicate with the low pressure chamber attached to the upper end of the deviceJ said opening independent of said fluid ducts, a normally open but hydraulically closable valve positioned within the ducts of the mandrel, said valve operating to remain in a normally open position when the tool is passing downwardly through iiuid at a normal speed, and movable upwardly to close said ducts against upward fluid ow when the tool is permitted to suddenly drop rapidly into the liner at a predetermined point, radially expanding the downfacing packer against the screen wall to eifect stoppage of the tool and to open the low pressure chamber and to hydraulically engage both packers to the screen wall when a charge is being taken into the tool.

WILSON TARKINGTON.

REFERENCES CTED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

